1. Field of the Invention
The present invention relates generally to the area of X-rays and more particularly to the conversion of X-ray film images to digital X-ray images.
2. Background Information
X-rays are among the most reliable and useful diagnostic tools in the treatment of injury and disease in both humans and animals. Although there are a variety of x-ray image systems, the most often used may be classified as either traditional x-ray film images or digital radiology.
In a traditional x-ray film system, an image is captured on a chemically treated x-ray film. The film is sensitive to radiation (usually x-rays) and exposure to x-rays causes the film to turn dark. X-rays tend to pass through materials such as muscle and skin, but are largely blocked by material such as bone. When a hand, for example, is interposed between x-ray film and the x-ray source, more of the x-rays are blocked by the bone in the hand than by the soft tissue in the hand and areas shadowed by the bone don't turn as dark. This results in a typical x-ray image with the more dense areas (bone) appearing white and the less dense areas being darker or black. Traditional x-ray film images are often referred to as being analog images.
Digital radiology (DR) produces an image similar to a traditional x-ray, but does not rely upon a reaction in a chemically treated film to an x-ray. DR uses an electronic plate to create a digital image which is ordinarily produced and stored in a computer. DR images aren't technically film x-rays, but they have the same general diagnostic use and appearance.
Traditional film x-ray systems and DR imaging systems have advantages and disadvantages. One of the chief advantages of traditional x-ray systems is a much lower initial cost. One of the chief advantages of a DR imaging system is the ability to manipulate the DR image after it is captured and saved on a computer. Various software is available for manipulating a DICOM image. DICOM is a widely accepted format for medical imaging. Unlike a traditional x-ray image, a DR image may be changed and enhanced by various operations such as cropping, edge enhancement, enlarging, changing contrast, and changing brightness.
Computed radiology (CR) is a kind of hybrid of traditional x-ray technology and DR image technology. CR systems use the same method of capturing an image as a traditional film x-ray system except instead of capturing the image on x-ray film, the image is captured on a photostimulable phosphor plate (PSP). The exposed PSP is scanned by a plate reader and the image is captured in DICOM format and may be manipulated using software in the same manner as a DR image. The traditional analog x-ray film image may be converted into a digital image by using a CR imaging system.
It is often necessary or desirable to change a traditional analog x-ray film image into a digital image which may be manipulated in the same manner as a DR image. For example, a doctor may want to compare an old x-ray captured on traditional x-ray film with a more recent image captured using DR or CR technology. Currently an analog X-ray film image may be converted to a digital image by taking a digital camera photograph of the old x-ray under very specific and controlled conditions. Most often these images are in a JPEG format and may be saved and manipulated to a very limited extent using conventional photo modification software. A JPEG image is not a useful as a DICOM format image because DICOM image software can be used to perform significant enhancements of the image which are not available when manipulating a JPEG image. For example, using conventional software, a DICOM image may be manipulated such that soft tissue such as a lung is emphasized and the bone portion of the image reduced.
The x-ray conversion method of the instant invention solves several problems relating to the conversion of traditional film analog x-ray images to digital images which may be manipulated and enhanced in the same manner as images created directly using a digital imaging system. The instant invention provides a method for directly converting traditional x-ray images to DICOM images using an inexpensive device coupled with existing CR equipment. In some instances, it may actually be possible to correct errors in the original X-ray film image.
The ideal x-ray conversion method should provide a simple method of converting traditional x-ray images to DICOM images with little or no loss of detail or accuracy. The ideal x-ray conversion method should take advantage of existing CR imaging equipment and software where possible. The ideal x-ray conversion method should also be rugged, inexpensive, easy to service, and easy to operate.